Embodiments of the inventive concept are directed to a method of forming a layout of a photomask, and more particularly, to a method of forming a layout of a photomask using optical proximity correction (OPC) to compensate for a three-dimensional (3D) effect of the photomask (hereinafter, referred to as a “3D mask effect”).
The development of photolithography technology has accelerated the scaling down of integrated circuits. Accordingly, the size of a pattern transferred onto a wafer may be smaller than the wavelength of an exposure beam. Thus, optical proximity correction (OPC) to compensate for light diffraction and interference has become an important process for fine and reliable micro-patterning. However, when using OPC, it may be necessary to compensate for a 3D mask effect.